Sliding doors and other door systems are known in the art for providing means of restricting and permitting access to structures. Sliding doors can be advantageous over swinging doors because they can provide a large opening without requiring as much space for the doors to swing.
While sliding doors are desirable for space reasons, some sliding door systems are difficult to seal. Many sliding door systems include some type of weather stripping or a brush along a lower edge of each door panel to form a seal with the floor surface. However, in order to effectively seal, these types of weather stripping or brushes must slide along the floor while the door system is being opened or closed. Accordingly, the weather stripping can wear rather quickly until it loses effectiveness at forming a seal. If the unit is adjusted downward in order to close the gap too much, the added friction will not allow the panel to slide freely.
Many attempts to just add brushes to reduce the friction will allow water and air infiltration. Moreover many of these types of systems do not have a way to reduce air infiltration at the header, typically they have some type of guide block in the header profile that guides the panel as it is sliding and only have some type of brush that glides against the panel. Thus, many of these systems cannot be easily reconfigured to compensate for the wearing of the weather stripping, or the gradual shifting of a door frame.
Some systems include relatively large lever handles on each door panel to allow a user to raise and lower the panel slightly (such as raised for sliding, lowered for sealing). Moreover, most of these systems cannot be adjusted via the wheels to compensate for a non-level floor. This means that once the panel is lowered to the sealing position, the panel resting on the non-level floor will not be level. On larger panels this becomes an issue due to the fact that the leading edge will not rest plumb against the jamb, which may prevent the panel interlockers from sealing and thereby allowing air infiltration.
One trend in the sliding door industry is to automate these systems so that a motor pulls and/or pushes all the panels open at the touch of a button. However, attempts to combine automated open and closure systems with a system that lowers to seal can be cost prohibitive. In certain instances, for example, the large handle required to leverage the heavy panels into the up and down positions that are mounted on each panel hinders the panel stack (e.g., many panels going in one direction) from stacking flush to each other in the open position. Moreover, in some instances, large handles may prevent the panels from going all the way into the pocket.